The deviation tool with the spring on the side and the drill head in the back as designed by the Copenhagen group. The spring is supposed to fit into the freshly broached groove down there in our bore hole at approximately 2327 m to 2352 m depth. Hence, the spring pushes the drill head to the opposite side of the bore hole to “ream”/mill into the wall and produce the wanted ledge.. Photo by G. Lawer.
